A friend of mine is using xmail, I'm trying to help them... their mail server is not accepting incoming username@[111.222.333.444] style addresses (where thats their IP). These are RFC822 compliant, and are used in some odd places...

I ran into this when they had problems with AOL rejecting their mail, and when I ran AOL's relay and complaint checks, they were going to send the response to root@[ip.add.re.ss] ... which bounces with a 'dsn=5.1.1 stat=user unknown' on the senders side, and a .... "RCPT=ERELAY" "" "0" "" on xmail's side.

... it's already implemented in 2.0. Currently XMail support receivingmessages to local IP domains like "x.y.z.w" or "[x.y.z.w]" by creatingalias domains for those IPs. And this will remain the same. Also, sendingto a remote IP "x.y.z.w" is working. What is not working in 1.x that willwork in 2.x is ending to a remote IP using the "[x.y.z.w]" syntax.